Sam DiMaria of British Columbia and other IFTA members look at Gala trees in plots at the Grove Research Center in Tasmania. Horticulturist Predo Jotic said the trees, which are on Malling 9 rootstocks with M.102 interstems, have not yielded well because
Establishing a high-density orchard involves a high initial investment that only pencils out if the grower receives a premium for the fruit. That’s why it’s important not to hesitate too long before going ahead and planting a hot new variety, says Predo Jotic, senior horticulturist at the Grove Research Station in Tasmania.
Jotic is conducting trials with Fuji, Pink Lady, and Sundowner to demonstrate how to produce crops in the second and third season after planting in order to take advantage of premium prices for new varieties while they last.
He figures that a planting with 2,000 trees per hectare (810 trees per acre) requires an investment of Aus.$30,000 per hectare (U.S.$9,615 per acre) and a planting with 4,400 trees per hectare (1,780 trees per acre) would cost Aus.$50,000 (U.S.$16,000) up-front.
If you have a hot variety like Honeycrisp or Jazz, you could plant a large number of trees, get early crops, sell them at a premium, and start making a profit, he pointed out.
"The main problem in this industry is people have been too slow to benefit from these new varieties," Jotic told members of the International Tree Fruit Association when they visited the research station. "They sit down and say, ‘Maybe I’ll do it or maybe not,’ and they miss the premium prices. You won’t get those again. They’re gone. With a hot variety, you want to go for it. If you’ve got Red Delicious, forget it."
At the station, a block of Gala on Malling 9 with M.106 interstems produced 39 tons per hectare (39 bins per acre) in the second leaf, which Jotic said was too much because the apples were too small. The trees were spaced 0.5 meters apart with 3 meters between rows (1.65 by 10 feet). The total cumulative yield for the first five crops was 200 tons per hectare (200 bins per acre).
Another block of Gala on M.9 on the same spacing but without interstems produced 250 tons per hectare by the sixth leaf.
"If you do everything right, you can aim at from 200 to 300 tons per hectare up to year six without any problems," Jotic said.
Good nursery trees
Such high early yields depend on good canopy development. The grower would need to use good nursery trees with 8 to 10 feathers and plant them at a density of between 3,000 and 3,500 per hectare (1,200 to 1,400 trees per acre).
A block of Gala on M.9 with M.102 interstems also planted on a 0.5- by 3-meter spacing produced a cumulative yield of only 180 tons per hectare by year six because of poor canopy development, Jotic pointed out. The nursery trees were not high quality and after six years in the orchard were still relatively weak. A small canopy produces lower yields, he emphasized.
"Really, what we ought to do is not grow the canopy here. We want to plant the canopy. We want nurseries to grow it for us and bring it here, and plant it, and crop it. That’s the best way."
In a trial with Sundowner, Jotic found that if he planted a whip and headed it at planting, the trees produced 16 tons of apples per hectare in the second leaf. Unheaded whips produced 30 tons, and trees with six feathers at planting produced 42 tons per hectare. With thinning and pruning, the feathered trees could produce 35 tons of good-sized fruit, he suggested. "That’s still a long way ahead of 16 tons."
Cost is an issue for a grower wanting to plant high quality trees at high densities. "If you want to go high density, you have to be creative," Jotic said. "Talk to the nurseryman about price, or grow your own trees."
There is a point beyond which increasing the tree density is not worthwhile, however. A test planting of Gala on M.9 with 13,332 trees per hectare (5,400 trees per acre) produced no more fruit in the first six years than a planting with half that number of trees.
Jotic recommends a more modest tree spacing of 1 by 3.5 meters (3.3 by 11.5 feet), for a total of 2,257 trees per hectare (914 trees per acre). If the nursery trees are good quality with feathers, canopy development should be good enough to give a crop of 40 or more tons per hectare in the second year and fill the space by the third leaf.